This protocol features a multicenter, open-label design which will evaluate safety, tolerance and antiviral efficacy. HIV-1+ males and females 14 years of age or older with HIV-1 RNA levels < or = 400 copies/mL newly enrolled patients from protocol M/3331/0021 will be treated with delavirdine (400 mg TID), zidovudine (200 mg TID) and lamivudine (150 mg based on body weight). This extension study consists of a single dosage group to be treated for 24 weeks with the option of continuing study participation for an additional 24 weeks if study participants remain < or= 400 copies.mL in viral load. Safety will be assessed at every 8 weeks. Viral burden will be measured by an FDA approved RNA PCR assay, and results will be provided to the investigators as baseline (which is M/3331/0021 end of study visit), weeks 8,16,24,32,40,48 and early D/C. This will be provided to investigators to assist in treatment decisions.